RatRod25 Posted June 8, 2009 Report Share Posted June 8, 2009 I have a weber on my 720 a 32/36. How do i adjust the air/fuel mixture? I think its the screw by the ide, but does turning it in lean it out or make it rich? Quote Link to comment
mazdat Posted June 8, 2009 Report Share Posted June 8, 2009 its not the screw by the idle and/or linkage, its the one screw all by itself towards the base of the carb, turn in the screw until the engine starts to shake and seems like its going to stall, then back out the screw about 1 1/2 turns . that should do it:) here's a pic of the carb and screw http://datsun1200.com/modules/myalbum/photo.php?lid=2926 Quote Link to comment
tlap Posted June 8, 2009 Report Share Posted June 8, 2009 Here is some good info from their web site. http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm Quote Link to comment
240ADAM Posted June 8, 2009 Report Share Posted June 8, 2009 Turn the air/fuel screw in all the way, then back it out till you get the highest idle speed you can then turn it back in a 1/4 turn. Then adjust your idle screw to get your desired idle. Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 its not the screw by the idle and/or linkage, its the one screw all by itself towards the base of the carb, turn in the screw until the engine starts to shake and seems like its going to stall, then back out the screw about 1 1/2 turns . that should do it I tried that, but it doesnt shake or die. Ive always done that on my bronco's edelbrock. But i tried it on the 720 and nothing. I do have a comp cam and a doug thorley header if that makes any differance. Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 Also it dies when i come to a stop, i have to give it gas to keep it going till it idles by its self Quote Link to comment
mazdat Posted June 8, 2009 Report Share Posted June 8, 2009 if you already turned the screw at the base of the carb all the way in and the engine didn't seem to shake or tried to stall, you have a bad carb, if it was recently rebuilt, they didn't do a very good job. just get it rebuilt:) Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 I bought it straight from weber its been like that out of the box Quote Link to comment
mazdat Posted June 8, 2009 Report Share Posted June 8, 2009 if its brand new, it must be a defective one, you are turning the bottom screw near the base, right? or you may have a vacuum leak at the intake manifold. with the engine running, spray some carb cleaner around the intake manifold, if the idle straightens out, you have a vacuum leak. Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 Its about a year old, but it was runnig just fine but i messed with the timing and carb to try and get some more power out of it but when i tried to put it back it was never the same Quote Link to comment
mazdat Posted June 8, 2009 Report Share Posted June 8, 2009 what exactly did you do to the timing? messed with the firing order or did you take the distributor out and reinstalled it? Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 advanced the timing and turned out the screw on the carb Quote Link to comment
mazdat Posted June 8, 2009 Report Share Posted June 8, 2009 sounds pretty simple what you did, should be able to retard the timing to where it was and undo the screw, you did that already. Hmm, are you sure that all the vacuum hoses ( if you have any) are hooked up? Because by advancing the timing and adjusting the air/fuel mixture, you should be able to put back where it was with ease and not complications. :confused: Quote Link to comment
RatRod25 Posted June 8, 2009 Author Report Share Posted June 8, 2009 I did that put the timing back and turned the screw back but i dont remember where it was. The only vaccuum hose thats hooked up to it is the vaccuum advance. I removed all the emission stuff ahile back, so i just have vaccuum caps on the other vaccuum ports Quote Link to comment
mazdat Posted June 9, 2009 Report Share Posted June 9, 2009 unless something gave in the engine, i douht it though. call me, i pm'd my # Quote Link to comment
Guest DatsuNoob Posted June 9, 2009 Report Share Posted June 9, 2009 I turned my screw all the way out till it ran like shit, then all the way in till it ran like shit, then picked the middle and it ran sweet :D Quote Link to comment
RatRod25 Posted July 19, 2009 Author Report Share Posted July 19, 2009 I need help ASAP!! im in the garage as we speak! lol Im trying to tune my carb but not gettin far. My ? is when the truck is fully warmed up and at idle is the choke suppose to be fully open? Mine is pretty much closed and dies out when i open it up Quote Link to comment
yello620 Posted July 19, 2009 Report Share Posted July 19, 2009 Engine warm the choke should be fully open or darn close. Have you followed the instructions for tuning a weber on the Racetep.com site? Very specific instructions and they are very different from most carbs for tuning. Quote Link to comment
datzenmike Posted July 19, 2009 Report Share Posted July 19, 2009 The choke plate should be OPEN. when warm. The reason it quits when you open it is because you have already turned the screw all the way in, so no fuel for idle. Quote Link to comment
datzenmike Posted July 19, 2009 Report Share Posted July 19, 2009 The stock 720 has an electric choke heater, usually the Blue wire at back pass side of carb. Hopefully you bought a Weber that is a direct replacement for the year of truck making it a bolt on operation and easier to set the initial adjustments. Quote Link to comment
RatRod25 Posted July 20, 2009 Author Report Share Posted July 20, 2009 The stock 720 has an electric choke heater, usually the Blue wire at back pass side of carb. Hopefully you bought a Weber that is a direct replacement for the year of truck making it a bolt on operation and easier to set the initial adjustments. Yeah i bought it from http://www.webercarbsdirect.com.. I tried to unscrew the idle mix all the way out and open it up and nothing still wants to die out.. If i spray carb cleaner in the carb while the choke is all the open it idles.. Quote Link to comment
RatRod25 Posted July 20, 2009 Author Report Share Posted July 20, 2009 Here is a pic of how open it is at idle engine fully warmed up.. Quote Link to comment
banzai510(hainz) Posted July 21, 2009 Report Share Posted July 21, 2009 open the choke then!!!!!!!!!!!!!!!! find the eleltric wire or loosen the 3 screw and turn the round thing till it opnes up when warm!!!!!!!!!! this is EZ this should take less time than pulling spark plugs!!!!!!!!!!! Quote Link to comment
F8d2blk1 Posted July 21, 2009 Report Share Posted July 21, 2009 open the choke then!!!!!!!!!!!!!!!! find the eleltric wire or loosen the 3 screw and turn the round thing till it opnes up when warm!!!!!!!!!! this is EZ this should take less time than pulling spark plugs!!!!!!!!!!! What if it dies when you open? Quote Link to comment
fastdadd Posted July 21, 2009 Report Share Posted July 21, 2009 http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm first thing it says is to make sure chock is wide open then set adjustments from there Quote Link to comment
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